This invention relates to the field of microwave oven doors, and more specifically to that class of microwave oven doors which are especially adapted to minimize the leakage of microwave energy at the oven-door interface.
For reasons of energy conservation, as well as compliance with government regulation, it is desirable to insure that microwave energy introduced into an oven cavity does not leak out. In fact, government standards set limits of maximum allowable energy emissions.
It has long been recognized that in many cases microwave oven leakage can be minimized by providing a close fit between the oven door and the front face of the oven. Ordinary manufacturing tolerances will cause unacceptable gaps to exist which will cause excessive leakage unless special measures are taken.
In the past such measures have included spring urged plates mounted in the door to force the plate into contact with the oven front when the door is closed. Other techniques have included the use of compressible gaskets or other elastic substances which allow the door to be pressed into a tight fit with the oven front.
Considerations of appearance and cost have dictated substantial changes in the construction of microwave oven doors in recent years. Modern consumer microwave ovens are typically constructed with a wide expanse of glass across virtually the entire door area. Accordingly, the door interior is no longer constructed of metal and the use of spring loaded metal contact plates or collars is no longer practical.
As illustrated in U.S. Pat. No. 3,843,859 to Eldon J. Klemp and Vernon Cassibo more modern microwave oven doors are constructed using a sheet of glass having a perforated metal sheet or screen laminated to the glass. This construction may also include a sheet of plastic, such as Mylar or Lexan, laminated over the metal screen. In this construction the metal screen is generally attached to the glass in a rigid manner, such as by gluing it directly to the glass. Because glass is a relatively inflexible material there is little opportunity in this construction for the inner surface of the door to conform itself to the shape or irregularities of the oven front panel.